Blog >> Different processes of manufacturing Soda Ash
Solvay process has another name as ammonia soda process, and uses salt (NaCl) and limestone (CaCo3) as raw materials. Ammonia, which is also used in the process, is almost totally regenerated and recycled. The reason why this process is famous because the availability of the raw materials. Raw materials can be found out almost everywhere in the world and therefore allows operating production units relatively closer to the market, Thus having negligible logistics cost.
The solvay process produces Light Soda ash, with density of around 500kh/m3.
It is used mainly for the detergent market and certain chemical intermediates
Soda ash Light is transformed by recrystallization firstly to monohydrate form of Sodium Carbonate and finally to dense soda ash which is mainly used in glass industry and has pouring density of 1t/m3.
Modification to this Process:
1. Dual process: Which allows production units to co-produce in nearly equal quantities ammonium chloride, which is also used in manufacturing of fertilizers used in rice cultivation.
2. Akzo or dry lime process, which uses dry lime instead of lime milk for ammonia recovery.
Trona and Nacholite based process:
All these process are based treatment of the ore from which the impurities have to be stored underground or in tailing ponds.
1. Mining using room and pillar or Long wall method.
2. Calcined to produce Soda Ash which is impure.
3. It is dissolved and solution is settled followed my filtration to remove the coarse impurities.
4. Filtration with Micro pore size membranes to remove fine impurities.
5. The purified liquor is sent to evaporators where crystallization occurs.
6. The monohydrate slurry is concentrated in centrifuge before drying and transformation into dense soda ash.
Deposits from trona lakes and solution mined trona are processed as follows:
1. Dissolving trona in wells
2. Carbonation of the solution
3. Filtration of the slurry
4. Calcination of the bicarbonate to get light grade of soda ash.
5. Monohydrate method is used to transform SAL to soda ash dense
6. Carbon dioxide enrichment
There are many more process like
Nepheline syenite process, Carbonation of Caustic Soda and so on.