Manufacturing process of coarse grained thenardite

The invention discloses a manufacturing process of coarse grained thenardite, which is characterized in that under the monitoring of a DCS automatic monitoring system and the control of AK liquid balancing flow-rate meter, raw glass gall with a given concentration which is conveyed in the well is mechanically removed foreign matters by a primary pipeline filter and is precisely purified by a four-stage ion exchanger to obtain refined glass gall with low content of foreign matter, after pH value of the refined glass gall is adjusted, the refined glass gall is inputted to a continuous crystallization process system, after continuous solid-liquid separation in a primary centrifugal, the refined glass gall is re-inputted to a multilevel screw-type vacuum dryer to be dried and dehydrated and then to be conveyed to a fluidized bed to be treated, and after mirabilite with coarse grain is separated, the coarse grained thenardite is obtained.