Many powders cannot survive the air temperature of a hot air dryer. The SZG-1000 double cone rotary vacuum dryer removes that constraint by drying at low temperature under vacuum: the jacketed twin cone rotates at 6 rpm while the vessel is held between -0.1 and 0.15 MPa, so moisture leaves the product at 40 to 60 °C and the material never meets an oxidizing air stream. Vitamin premix, enzyme granule, thermo labile pigment and crystalline product all keep their colour,