A fluidized bed is a device that suspends a large number of solid particles in a moving fluid so that particles have some apparent characteristics of the fluid. This fluid-solid contact state is called solid fluidization. This device is called a fluidized bed. Fluidized beds are widely used in salt drying and cooling. Fluidized beds are usually divided into fixed fluidized beds, internal heating fluidized beds and vibrating fluidized beds. Uniform fluidization greatly reduces energy consumption, wear between particles and dust entrainment; uniform distribution of material residence time can be considered as "piston flow", and residence time is easy to adjust and control, so very ideal moisture content of products can be obtained.