Nano filtration device, and nano filtration preposed mine water treatment system and process

The invention discloses a nano filtration device, and a nano filtration preposed mine water treatment system and process. The system comprises a pretreatment device, a nano filtration device, a concentration device and a sodium chloride crystallization device, wherein the pretreatment device, the nano filtration device, the concentration device and the sodium chloride crystallization device are sequentially connected. The process comprises the steps that mine water is pretreated through a pretreatment device, suspended solids, scaling ions, fluoride and COD in the mine water are removed, the pretreated mine water enters the nano filtration device to be subjected to multi-stage nano filtration treatment so as to intercept divalent ions in the mine water, nano filtration produced water of the nano filtration device is directly recycled or discharged after reaching the standard, nano filtration concentrated water of the nano filtration device enters the concentration device for concentration treatment, and conce