Verfahren zur Aufkonzentrierung von Dünnsäure

摘要

This invention relates to a method for concentrating dilute acid containing metal sulfate in a three-stage, forced circulation evaporator system. The dilute acid is conveyed to the first stage and a concentrated sulfuric acid is drawn off from the third stage. Steam and/or vapor is used as a heating medium, the vapor that is not used as a heating medium being condensed. At least part of the flow of dilute acid is conveyed to the evaporator vessel of the first stage. Drops of the dilute acid to be concentrated that are carried with the vapor from the bottom of the evaporator vessel are separated in the evaporator vessel of at least one stage and of fed back into the bottom of the evaporator vessel. This results in an improvement in evaporating efficiency.