| 摘要 |
A method and a device for recovering crystals from a solution by evaporation with crystallisation in an evaporation plant having at least two stages are disclosed. In the method, the crystallised salt is separated in each evaporation stage (n) from mother liquor and is, in all stages except the first, dissolved to a substantially saturated solution, which is then conducted to the preceding evaporation stage (n-1). The crystallised salt in the first evaporation stage of the plant is collected as final product. The device comprises at least two evaporators (I1, I2, I3) with an inlet (1, 2, 3) for heating medium, and an inlet (6, 11, 14) for the solution to be evaporated, and an outlet (7, 12, 16) for the evaporated solution. The outlet of each evaporator (I1, I2, I3) is provided with separating means (C1, C2, C3) for separating crystals from mother liquor. The inlet of an evaporator (I1, I2...In-1) is connected to the separating means (C2, C3...Cn) of the subsequent evaporator (I2, I3...In) for receiving crystals from the separating means, and to a supply means (5) for liquid which forms, with the crystals, a substantially saturated solution which is to be evaporated. The outlet (10) for crystals from the separating means (C1) of the first evaporator (I1) of the device is the product outlet. |
