Fluid bed dryers work on the principle of fluidization, a process in which hot air is introduced into the spaces between solid particles. Each particle is in direct contact with, and surrounded by, the hot air – creating an efficient and uniform drying process. The material is dried in the first section of the machine and cooled in the second. Most minerals can be dried using evaporative cooling. Evaporative cooling means that the last part of the moisture is evaporated in the cooling section, instead of in the dryer section of the fluid bed system. The product is not completely dried to < 0.5 % moisture. Instead of this it is dried to ± 1 %. The rest of the moisture is dried off in the cooling section of the fluid bed system.