Caustic liquor processing pumping

When manufacturing solid sodium hydroxide on industrial scale a caustic solution containing 50 per cent NaOH is evaporated. This is either done directly into the final product or by an intermediate concentration to a 75 per cent NaOH solution. For intermediate concentration a standard single-effect vacuum evaporator is used. As no salt is separated in the course of this evaporation process, the design of the evaporator is very simple. All pumps as well as the piping must be steam jaeketed to prevent the solidification of the highly concentrated liquor. 

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