METHOD OF RECYELING OF BY-PRODUCTS FOR PRODUCTION OF SODA ASH AND AMMONIUM SULPHATE

摘要

The present invention discloses a method of recycling of by-products of Merseberg process and Solvay process in the integrated process for the production of soda ash and ammonium sulphate in integrated manner employing brine, ammonia and CO2 as raw materials. Novel synergy between (i) the Solvay process backward integrated to pure solar salt production through forced separation of gypsum using CaCl2-containing waste of the Solvay process and (ii) the Merseberg process wherein gypsum produced above, ammonia and CO2 are reacted together to obtain ammonium sulphate and calcium carbonate has been disclosed. Besides the utility of ammonium sulphate as a fertilizer, the calcium carbonate so generated can be recycled in the Solvay process, which reduces the need for quarrying of limestone. Indeed, if the entire distiller waste can be converted into gypsum, limestone requirement can be dispensed with altogether. Further, the CO2 required for the Merseberg process is obtainable from the flue gas generated from the plant which helps to curtail greenhouse gases to some extent. Such integration entails little additional complexity as both processes involve similar operations. The desulphated bittern left over after separation of common salt can be processed further for KC1 recovery via intermediate carnallite as disclosed in the prior art.[IN-DEL-2010-00930A]