In respect of the producing method, refined and high unmixed salt is usually made by multipleeffectevaporation in vacuum, when man-made bittern is needed.
从制取方法上来讲,多效真空蒸发制盐是生产精制盐及高纯工业盐的重要方法。
2
Multiple-effectevaporation can be classified as a variable hot and cold sink system. The minimum utility of this kind of system must bet he case where multiple pinch points occur.