| 摘要 |
Disclosed is a method for the continuous manufacture of higher-strength, lower-salt, aqueous sodium hypochlorite bleach from a lower-strength aqueous sodium hypochlorite bleach that has some sodium hydroxide and that is essentially free of sodium chloride (salt) crystals, the method comprising: A) in a tank, sustaining a continuous reaction that produces a slurry of higher strength bleach and solid salt crystals by introducing into the tank 1) the lower-strength aqueous sodium hypochlorite bleach that has some sodium hydroxide and is essentially free of salt crystals, 2) aqueous sodium hydroxide solution having a concentration by weight within a range from about 45% to about 51%, and 3) chlorine in gas and/or liquid phase that mayor may not include inerts, and 4) a recycle solution; B) continuously withdrawing slurry from the tank at a level below where the lower-strength bleach, the sodium hydroxide solution, the chlorine, and the recycle solution begin to mix with slurry already in the tank; C) cooling a first portion of the withdrawn slurry and using the cooled first portion of the withdrawn slurry as the recycle solution; and D) processing a second portion of the withdrawn slurry to separate substantially all salt crystals from the second portion of the withdrawn slurry to form a residual liquid; and E) recovering the residual liquid as the higher-strength lower-salt, aqueous sodium hypochlorite bleach.
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