| 摘要 |
The method is waste free and ecologically clean. By using it the purity and the amount of the yield of end products increases. The method uses interaction between ammonium sulphate and sodium chloride at pH value 6.5 for 30 to 45 minutes in an environment of parent lye and rinsing waters from previous cycles. The weight ratio between the ammonium sulphate, sodium chloride and the medium is 1 : 0.8 - 1.2 : 1.5. The reacting mixture is slightly heated up to 90 degrees C by gradually feeding the raw materials. The prepared suspension is filtered, the crystals of sodium sulphate are consecutively rinsed with a mixture of lye and rinsing waters heated at 80 to 95 degrees C. Afterwards they are washed with hot water and are dried. The filtrate is cooled down to 15-42 degrees C. The crystallized ammonium chloride is filtered, rinsed with water at temperature 40 to 60 degrees C and dried at temperature of up to 150 degrees C. The parent lye and all rinsing waters are collected for forthcoming cycles.
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