Question

Can someone give file of the article about solvay process to manufacture the sodium carbonate

Answer 1

Solvay process is a continuous process for the production of sodium carbonate (Soda ash).

The raw materials required in process are salt (NaCl), limestone (CaCO3),ammonia (NH3), water.

The first step is the preparation of brine solution by dissolving NaCl in water (30% brine solution is prepared).

Brine is counter contacted with ammonia in absorber ( the ammonia is recycled from the ammonia recovery column and may contain some traces of carbon dioxide). The brine solution gets saturated with ammonia.

The withdrawn stream from the bottom of the absorber is then filtered through which calcium carbonate and magnesium carbonates precipitates. The filtered ammonium carbonate is then sent to carbonation tower where it is counter contacted with carbon dioxide gas. Both reacts to form insoluble sodium bicarbonate.There is also some ammonium chloride and ammonium bicarbonate coming out in solution which are pumped to ammonia recovery tower.

The obtained sodium bicarbonate is heated to form sodium carbonate with the remirem of carbon dioxide and water.

The carbon dioxide used in the process is obtained from lime kiln where Calcium carbonate is heated to produce CaO and CO2.

The produced CaO is mixed with water to produce Calcium hydroxide (slaked lime).

The filtered ammonium bicarbonate and ammonium chloride are pumped into ammonia recovery tower ( for economy purpose as ammonia is costly and needs to be recovered) and mixed with slaked lime to obtain ammonia, Calcium chloride and water.

The various reactions involved in the process as described above and the process flowsheet is given below.