Device for preparing sodium carbonate by using carnallite

The utility model discloses a device for preparing sodium carbonate by using carnallite. A discharge hole of a carnallite storage tank is respectively communicated with a mother liquor barrel and a second crystallizer; a first pump, a first absorption tower, a second pump, a membrane filtration device, a third pump, a second absorption tower, a first crystallizer, a third absorption tower and a fourth pump are sequentially connected between a mother liquor barrel discharge port and a mother liquor feed port of the second crystallizer; a mother liquor outlet of the second crystallizer is communicated with a liquid inlet in the bottom of the mother liquor barrel, and a solid product outlet in the bottom of the second crystallizer is communicated with centrifugal drying equipment; the bottoms of the first absorption tower and the third absorption tower are connected with an ammonia input pipeline; the bottom of the second absorption tower is connected with a carbon dioxide input pipeline; the bottom of the first