Raw materials

Process flow diagram

Steps involved in production

• Salt (NaCl)

• Lime stone

• Coal

• Ammonia

• Deionized water

NaCl+CaCO3 Na2CO3 +CaCl2

However……..

1- Ammonia absorption

Saturation of salt solution with ammonia

bubble and cap absorber

2- Burning of limestone to produce carbon dioxide and lime

Combustion of C to CO2 (highly exothermic and produces 96.5 Kcal/mole of C burnt)

Decomposition of 1 mole of CaCO3 need 43.44 Kcal

Thus mixing lime with coke…….

3- The Solvay tower/carbonation of ammoniated brine

4- Separation of Sodium Bicarbonate

Filtering and washing of precipitated bicarbonate

5- Thermal decomposition of NaHCO3 to Na2CO3 (Calcination)

6- Production of milk lime (calcium hydroxide)

7- Regeneration of ammonia

Soda ash can be classified into two forms –

heavy and light.

Product after calcinations is called light form is obtained first and some is then converted into the heavy form containing less than 0.5% sodium chloride.

Heavy sodium carbonate is obtained by hydrating light sodium carbonate to the monohydrate (Na2CO3.H2O) and then dehydrating it to give a product with an increased crystal size and density.

The two grades have different uses.

The major uses of heavy sodium carbonate are as a solid, particularly in making glass, where it is used as a flux in the melting of silica (sand).

The uses for light sodium carbonate are traditionally where the chemical is required in solution.

Sodium carbonate, is used

In the manufacture of glass, paper, rayon, soaps, and detergents.

As a water softener To control pH (carbonate solutions neutralize acids,

producing only carbon dioxide and water). In the chemical industry to synthesize many different sodium

compounds, including sodium bicarbonate (baking soda), sodium silicate (used in detergents), sodium tripolyphosphate(a detergent builder), sodium hydroxide (lye), sodium chromate and sodium dichromate (used in chrome plating), sodium aluminate (used in refining aluminum), and sodium cyanide (for electroplating).