Six-effect hot-process saltpeter extraction process

The invention relates to a process method for preparing salt, in particular to a sextuple-effect hot-process saltpeter extraction process. The method comprises the following steps that steam sequentially enters an I-effect heating chamber, an II-effect heating chamber, an III-effect heating chamber, an IV-effect heating chamber, a V-effect heating chamber and a VI-effect heating chamber through a heat pump and is heated and evaporated in salt evaporation tanks of all the effect heating chambers, the temperature of secondary steam subjected to II-effect evaporation is 105-110 DEG C, the secondary steam enters a saltpeter separation tank for saltpeter separation, and part of live steam enters a drying bed to be dried; raw brine is sequentially preheated and heated through a plate heat exchanger and then enters an effect salt evaporation tank IV, an effect salt evaporation tank V and an effect salt evaporation tank VI, old brine is sequentially preheated and heated through the plate heat exchanger and then enter