The production trajectory of the special dryer for chromium nitrate: under the stirring of the rotating teeth of the positive and negative rotation, the material moves back and forth in the axial direction, and the surface in contact with the inner wall of the vacuum dryer is continuously updated, and is indirectly heated by steam. The uniform stirring of the molars and the pulverization of the pulverizing rods make the surface moisture of the material more favorable to discharge, so that the materials form a continuous circulation state in the cylinder, thereby further improving the uniform heating of the materials. The object of the dryer is added from the upper part of the upper part of the casing, and the vaporized water is vented from the outlet of the vacuum pump through the dry dust collector, the wet dust collector and the condenser. The heating or cooling of the dryer needs to be carried out slowly, and the user should take it according to the situation. Suitable speed of rising and cooling.