| 摘要 |
The present invention refers to a process for transforming a filtered solution of ammonium chloride generated by the SOLVAY process into ammonium sulphate, which comprises as main impurities: sodium chloride, sodium bicarbonate and ammonium bicarbonate. The process comprises a first stage, which consists in acidifying the solution of ammonium chloride with sulphuric acid and cooling said solution at temperatures lower than 0 degree C, for the purpose of transforming the whole sodium salts into carbon dioxide and sodium sulphate, the same is crystallized as a deca hydrate and separated by centrifugation. The solution resulting from the aforesaid process is treated with sulphuric acid so as to form ammonium acid sulphate and hydrochloride acid, which is separated by distillation. The distillation residue is a solution of ammonium acid sulphate, which is neutralized with ammonia so as to form ammonium sulphate. The hydrochloride acid resulting from the aforesaid process is reacted with ground l imestone so as to form a solution of 36% of calcium chloride that is free of sodium chloride and carbon dioxide; said solution is used in the SOLVAY process instead of CO2 gas generated by limestone and coke in vertical furnaces.
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