| 摘要 |
The process according to the invention comprises suspending slaked lime in the aqueous solution resulting from the second chlorination stage after separating the solids formed therein, passing chlorine gas into the suspension at from 35 to 45 DEG C until the lime content in the suspension has dropped to from 40 to 55% by weight of the original value, separating the mother liquor from the solid formed, suspending once again the solid in water in a proportion of from 1 to 1.5 parts of water per part of solid, setting the pH of the suspension to between 13 and 14 by using an aqueous sodium hydroxide solution, passing gaseous chlorine into the suspension at a temperature which is 10 DEG C lower than at the first chlorination stage, continuing the chlorine infeed until the pH of the suspension has dropped to between 10 and 9, separating the solid from the mother liquor, which is recycled, washing the solid with water and drying the washed product at a temperature below 80 DEG C to a residual water content of less than 10 % by weight. In the process, a bleaching powder is obtained having a content of active chlorine of more than 70%.
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