Method of recycling of by-products for the production of soda ash and ammonium sulphate
First Claim
1. A method of recycling of by-products of Merseberg process and Solvay process in an integrated process for the production of soda ash and ammonium sulphate employing brine, ammonia and CO2 as raw materials, the process comprising the steps of:
- i. treating the brine with soda ash distiller waste for desulphatation of brine to obtain gypsum;
ii. recovering pure salt from desulphated brine and utilizing it in manufacture of soda ash in Solvay process;
iii. washing the gypsum obtained in step (i) and reacting it with liquor ammonia and carbon dioxide to obtain CaCO3 and ammonium sulphate;
iv. separating CaCO3 from the ammonium sulphate solution obtained in step (iii), and recovering solid ammonium sulphate from the solution;
v. washing the CaCO3 obtained in step (iv) followed by calcination to generate CO2 and lime;
vi. recycling the CO2 from step (v) in the Solvay process to obtain soda ash;
vii. recycling the lime from step (v) with ammonium chloride generated in the Solvay process to recover ammonia and obtain distiller waste as a by-product;
viii. recycling the by-product distiller waste containing CaCl2 obtained in step (vii) for the desulphatation of brine in step (i); and
ix. recycling ammonia recovered from step (vii) in step (iii).
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Abstract
A method of producing soda ash and ammonium sulphate by recycling by-products of Merseberg and Solvay processes includes treating brine with soda ash distiller waste for desulphatation of the brine to obtain gypsum, recovering pure salt from the desulphated brine and utilizing it in manufacture of soda ash in a Solvay process, washing the gypsum and reacting it with liquor ammonia and carbon dioxide to obtain CaCO3 and ammonium sulphate, separating the CaCO3 from the ammonium sulphate solution and recovering solid ammonium sulphate, washing the CaCO3 followed by calcination to generate CO2 and lime, recycling the CO2 in the Solvay process to obtain soda ash, recycling the lime with ammonium chloride generated in the Solvay process to recover ammonia and obtain distiller waste containing CaCl2 as a by-product, recycling the by-product distiller waste for the desulphatation of the brine, and recycling the ammonia recovered.
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Citations
9 Claims
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1. A method of recycling of by-products of Merseberg process and Solvay process in an integrated process for the production of soda ash and ammonium sulphate employing brine, ammonia and CO2 as raw materials, the process comprising the steps of:
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i. treating the brine with soda ash distiller waste for desulphatation of brine to obtain gypsum; ii. recovering pure salt from desulphated brine and utilizing it in manufacture of soda ash in Solvay process; iii. washing the gypsum obtained in step (i) and reacting it with liquor ammonia and carbon dioxide to obtain CaCO3 and ammonium sulphate; iv. separating CaCO3 from the ammonium sulphate solution obtained in step (iii), and recovering solid ammonium sulphate from the solution; v. washing the CaCO3 obtained in step (iv) followed by calcination to generate CO2 and lime; vi. recycling the CO2 from step (v) in the Solvay process to obtain soda ash; vii. recycling the lime from step (v) with ammonium chloride generated in the Solvay process to recover ammonia and obtain distiller waste as a by-product; viii. recycling the by-product distiller waste containing CaCl2 obtained in step (vii) for the desulphatation of brine in step (i); and ix. recycling ammonia recovered from step (vii) in step (iii). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification